Many chemicals have been produced using materials originated from coal, petroleum, or other fossil materials. However, for the prevention of the global warming and the protection of the environment, the use of renewable biological resources as carbon resources has been recently attracted the attention as an alternative to conventional fossil materials. For example, techniques of the use of biomass resources have been developed. Examples of the biomass resources include starch-based biomass such as corn or wheat, sugar-based biomass such as sugarcane, and cellulose-based biomass such as rapeseed cake or rice straw.
For example, polylactic acid derived from lactic acid (lactic acid monomer) that is produced from sugar by fermentation is a typical chemical made from biomass. Further, the use of lactic acid as raw materials for other chemicals has been investigated. For example, lactic acid esters are used as solvents, and have been investigated for conversion to an acrylic acid species or a pyruvic acid species.
The reactions for producing other chemicals from lactic acid include a gas-phase reaction in which chemicals are produced by vaporizing raw materials including lactic acid and bringing the vapor into contact with a catalyst.
For example, gas-phase dehydration using a solid catalyst is known as a technique for the production of acrylic acid from lactic acid (Non-Patent Literature 1 described below).
Further, Patent Literature 1 discloses a method for synthesizing an α,β-unsaturated carboxylic acid by introducing an aqueous solution of an α- or β-hydroxy carboxylic acid to a packed portion of inert ceramic or the like or an acidic solid catalyst, and heating the solution.